The present invention is directed to a system and method for flying a rotary wing aircraft having a coaxial main rotor assembly and, in particular, to controlling a rotor torque and rotor speed of the aircraft.
Rotary wing aircraft such as helicopters include a main rotor assembly having a rotor and rotor blades that sits atop a fuselage of the aircraft. An engine or electric motor of the aircraft applies a torque to the rotor in order to cause the rotor to rotate at a selected rotor speed, thereby providing lift to the aircraft. Current flight control systems for rotary wing aircraft generate and pass a suitable rotor speed reference value to an engine or electric motor control system which makes the actual rotor speed track the reference value. Such flight control systems are suitable for tracking slow changes in rotor speed. However, faster changes in rotor speed, such as those changes that occur at the on-set of aggressive aircraft maneuvering, cannot be accommodated by these flight control systems.